Graphic scanning apparatus with flexible optical fibres

ABSTRACT

IN A FACSIMILE SCANNER AN ENDLESS BELT IS DRIVEN BY WHEELS ON TWO STRAIGHT PATHS ONE OF WHICH PASSES PARALLEL TO AN ORIGINAL DOCUMENT, OR AN IMAGE THEREOF, FED AT RIGHT ANGLES TO THE PATH OF THE BELT. A HOLLOW SHAFT IS COUPLED TO THE BELT TO ROTATE AT THE SAME R.P.M. ONE END OF A FLEXIBLE OPTICAL PICKUP FIBER IS HELD ON THE BELT VIEWING THE DOCUMENT. THE OTHER FIBER IS CARRIED AXIALLY IN THE HOLLOW SHAFT AND DIRECTED AT A PHOTOTUBE. AS MOVEMENT OF THE BELT CAUSES THE FIRST FIBER END TO SCAN THE DOCUMENT ALONG ONE STRAIGHT LINE PATH, THE FIBER INTERMEDIATE ITS ENDS FLEXES AS THE DISTANCE BETWEEN THE TWO ENDS OF THE FIBER VARIES. ADDITIONAL FIBERS ADJACENT THE PICKUP FIBER CONDUCT LIGHT TO THE DOCUMENT FROM A LAMP ROTATING WITH THE HOLLOW SHAFT, ILLUMINATING THE AREA OF THE DOCUMENT TO BE SCANNED BY THE PICKUP FIBER. BY COLOR FILTERING TWO OR MORE ADJACENT PICKUP FIBERS A COLOR DOCUMENT IS SCANNED AND ELECTRICAL COLOR SIGNALS GENERATED SEQUENTIALLY BY ONE PHOTOTUBE OR SIMULTANEOUSLY BY SEVERAL PHOTOTUBES. ALTERNATIVELY SEVERAL FIBERS SCAN A TRANSVERSE ZONE OF THE DOCUMENT SIMULTANEOUSLY INTERSECTING CHARACTERS THEREON AND ENERGIZING A PLURALITY OF PHOTOCELLS FOR ELECTRICAL RECOGNITION OF SUCCESSIVE CHARACTERS. LIGHT FROM A LAMP MODULATED BY A FACISIMILE SIGNAL SOURCE MAY BE CARRIED BY FIBERS INTO PHOTOSENSITIVE PAPER SCANNED BY THE MOVING ENDS OF THE FIBERS TO RECORD THE FACISIMILE SIGNALS ON THE PAPER.

United States Patent [72] Inventor Frederick W. Sirnpkins PrimaryExaminer-Walter Stolwein Hanover, Mass. Attorney-Roberts, Cushman &Grover [21] Appl. No. 857,149 [22] Filed Sept. 11, 1969 [45] pammed June23 97 ABSTRACT: In a facsimile scanner an endless belt is driven [73]Assign m Research Foundation by wheels on two straight paths one ofwhich passes parallel to westbom, Mm an original document, or an imagethereof, fed at right angles to the path of the belt, A hollow shaft iscoupled to the belt to rotate at the same r.p.m. One end of a flexibleoptical pickup 54 GRAPHIC SCANNING APPARATUS WITH fibenis held on beltviewing the document. The other fiber FLEXIBLE OPTCAL FIBERS end IScarried axially 1n the hollow shaft and directed at a 23 claims 12 Dnwmg18$ phototube. As movement of the belt causes the first fiber end toscan the document along one straight line path, the fiber in- [52] U.S.Cl 250/227, Immediate its ends flexes as the distance between h two ends250/2 350/96 of the fiber varies. Additional fibers adjacent the pickupfiber [51] Int. Cl G02!) 5/16, conduct light to the documem from a lampmtafing with the 3/06 hollow shaft, illuminating the area of thedocument to be [50] Field of Search 250/227, Scanned by the pickup fibeLBy color filtering two or more 219 (I), (DTL 226; 350/96 (B); jacentpickup fibers a color document is scanned and electri- 6 fleck) (E) calcolor signals generated sequentially by one phototube or simultaneous]by several phototubes. Alternatively several [56] References Citedfibers scan a tiansverse zone of the document simultaneously UNITEDSTATES PATENTS intersecting characters thereon and energizing aplurality of 2,939,362 6/1960 Cole l78/7,6X photocells for electricalrecognition of successive characters. 2,982,l75 5/1961 Eisler 250/227XLight from a lamp modulated by a facsimile signal source may 3,043,1797/1962 Dunn... 250/227X be carried by fibers into photosensitive paperscanned by the 3,408,497 10/1968 Lowe 350/96X moving ends of the fibersto record the facsimile signals on the 3,436,757 4/1969 Schwab 250/227Xpaper.

9 r J 1 ID 4 f j .1? 4

g\\ \\l\ \l 2 2; if 1 m III III/I/lII/IIIIII/r PATENTEU JUH28 197i SHEET3 BF 3 GRAPHIC SCANNING APPARATUS WITH FLEXIBLE OPTICAL FIBERS Thisinvention relates to graphic scanners, both those which scan a documentor image thereof line by line and generate electrical signals therefrom,and those which receive facsimile signals and record them line by lineby scanning sensitive paper and marking the facsimile signals thereon.In each case an image plane is traversed effectively by one or moreflying spots which either apply modulated light to or pick up modulatedlight from the image plane. It has been found that lightconducting rodsare useful for transmitting the modulated light to or from the imageplane, but hitherto the end of such a rod constituting the flying spothas been moved on a circular path relative to the image plane.Consequently the facsimile signals represent an arcuate line of theoriginal document which is incompatible with the almost universallyaccepted straight line scanning equipment, as in U.S. Pat. No.3,192,391. Or some additional circle-to-line converter must be insertedbetween the light-conducting rod, as in U.S. Pat. No. 3,365,580, addingto the expense and complexity of the scanner without any improvement inits operation.

The object of the present invention is to provide a graphic scannerwhich employs optical light conductors, and which permits a straightline scan.

According to the invention a graphic scanner comprises a flexibleorbiting carrier, means to drive the carrier on an elongate closed pathparallel to an image plane, a rotating member coupled to said carrier torotate in synchronism therewith, a stationary light transducer, anda'flexible light transmission fiber having one end connected to saidcarrier and movable therewith to scan said image plane on said elongatepath, the other end of said fiber being held substantially axially onsaid rotating member, and an intermediate length of said fiber beingfree to flex as the distance between the two ends of the fiber varies.

For the purpose of illustration typical embodiments of the invention areshown in the accompanying drawings in which:

FIG. I is a slide elevation of a facsimile scanner according to theinvention, parts being broken away;

FIG. 2 is an isometric, schematic plan view of the scanner, parts beingomitted;

FIG. 3 is an enlarged elevation of a scanning belt in the scanner ofFIGS. 1 and 2;

FIG. 4 is a section on line 4-4 of FIG. 3;

FIG. 5 is an enlarged section on line 5-5 of FIG. 4;

FIG. 6 is an enlarged detail of a modification of the scanner of FIGS. 1and 2;

FIG. 7 is an isometric view of a further modification of the scanner;

FIG. 8 is an isometric, schematic view of a two-speed scannerofdifferent widths of documents;

FIG. 9 is an electromechanical schematic diagram of a speed changedetail of the scanner of FIG. 8;

FIG. I is an optical diagram of a still further modification of thescanner of FIGS. 1 and 2 for simultaneous color scanning;

FIG. 11 is a section like FIG. of a modification of the scanner forcharacter recognition; and

FIG. 12 illustrates a detail of the scanner of FIG. 1 modified forrecording.

Shown in FIGS. 1 to 5 is a facsimile scanner for a document D, or othergraphic matter, comprising a housing formed by a base I, a cover plate 2and a cover 3. The base I and cover 3 form an entrance 4 admitting thedocument into the housing onto the cover plate. On insertion through theentrance 4 the document is gripped between a driven roll 6 and an idlerroll 9, and fed in the direction of the arrow along the cover plate 2,and thence through an exit 12 from the housing. A second idler roll 8 isslightly smaller in diameter than roll 9 and is rotated by a belt 7 at aslightly slower peripheral speed so as to drag on the paper and hold thedocument tight between rolls 8 and 9. During feed along the cover plate2 the document passes over a narrow aperture 13 in the plate 2, whichaperture extends transversely of the document feed and is longer thanthe document is wide. Projecting through the aperture 13 from below thecover plate 2 is one of three riders 14 carried on an endless, toothedscanning belt 16. The belt is orbited on a sprocket wheel I7 driven by amotor M and an idler wheel 18 so that the riders 14 successivelytraverse the aperture 13 parallel to the image plane of the document. Oneach rider are mounted the ends of a cable 19 of optical,light-transmitting fibers 21 and 22. In each cable a group of fibers 21transmit light from a lamp 23 to the rider 14 and onto a spot of thedocument D. At least one fiber 22 in each cable picks up the illuminatedspot on the document as modulated by the dark and light graphic materialon the document and transmits the modulated light to the other end ofthe fiber which is directed at a phototube 24 in a light-tight housing20. As the riders scan successive transverse lines of the movingdocument, corresponding series of light modulations are converted intoelectrical facsimile signals by the phototube, which here acts as alight-to-electrical signal transducer.

As shown particularly in FIG. 2 the motor M driving the belt sprocketwheels 17 and 18 is linked by a shaft 26, pulley 27, belt 28 and pulley29 to a hollow shaft 30 which is journaled at its other end in thehousing 20 into which it projects toward the phototube. The ratio ofpulleys 27 and 29 is selected so that the shaft 30 rotatessynchronously, that is, at the same r.p.m., as the belt 16. One end ofthe shaft 30 carries a worm 31 meshing with a gear 32 on shaft 33. Theshaft 33 is linked to the document drive roll 6 by a belt 36 and pulleys34 and 37 selected in a ratio to drive the document at a linear speedcorrelated with the frequency with which the riders 14 on the scanningbelt 16 traverse the scanning aperture 13, the correlation causinglengthwise feed of the document at the line by line scan rate of theriders.

In FIGS. 3 to 5 are shown enlarged details of the fiber cable 19 and itstermination at the riders 14 on the scanning belt 16. The scanning belt16 has an elastomeric cylindrical body 41 with metal pins 42 projectingon each side where they are engaged by the teeth 43 of the sprocketwheels 17 and 18 (FIG. 4). Each rider 14 comprises a small U-shapedmetal frame 44 whose underside is curved to conform to the cylindricalbelt body 41. The block is simply and securely tied to the belt by astrand 45 of nylon monofilament passed through bores in the frame andknotted at each end of the frame. A bolt 46 fits loosely in bores 47through each upstanding arm of the U- shaped frame and extends throughthe threaded bore 49 of a Teflon plastic block 48 so that turning thebolt adjusts the block lengthwise of the frame 44 and belt 16. The boltis locked by a nut 51. Each rider is initially spaced approximatelyone-third of the belt length from the other riders, that is, equivalentto spacing on a circle. Fine adjustment to precise 120 spacing isaccomplished by the bolt 46. Underneath the scanning aperture 13 is aguide rail 52 which loosely conforms to the lower cross section of thebelt body 41 and teeth 42. A track 53 of Teflon plastic extendingparallel to the scanning aperture 13 bears against the rider block 48guiding the block on a precise straight line along the aperture. Screws56 through an elongate slot in the track 53 adjustably secure the trackto the guide rail 52.

Anchored in each rider block 48 is a fine, hollow metal tube 51enclosing the fibers 21 and 22 of each cable and protecting them againstexcess flexing and wear adjacent the belt 16. The end of the tube curvesoutwardly of the block 48, terminating flush with a curved recess 50 inthe end of the block bearing against the document D. The depth of therecess, about 0.0005 to 0.001 inch spaces the tube end slightly from thedocument to reduce wear and accumulation of matter on the tube end andto permit the light supplying fibers 21 to illuminate an area of thedocument viewed by the light pickup fiber 22. As shown in FIG. 5 thetube holds a group of six lightsupplying fibers 21 around a centrallight pickup fiber 22. Any desired number of supply and pickup fibersmay be used.

From the tubes 51 each group of fibers 19 extends to a support disc 38carried on the hollow shaft 30. There each of the three light pickupfibers 22 separates from the light supply fibers and enters the hollowshaft wherein they extend to the end of the shaft substantially axiallythereof and substantially anchored with respect to the phototube 24 atwhich they are directed, although rotating on the shaft axis. From thesupport disc 38 the light supply fibers 21 run together into a housing39 for the lamp 23. The housing 39 is fixed on and rotates with theshaft 31) as does a slipring 40 which supplies current to the lamp frombrushes 55. Between the support disc 38 and the riders 14 the fibers areslack and free to flex as the distance between the riders and discvaries during rotation of the disc and orbiting of the carrier. Thediameter of the disc 38 and radial spacing of the fibers should be asgreat as space allows to minimize flexing of the fibers.

Light from the lamp 23 is transmitted by the supply fibers 21 from thelamp 23 to their other ends on the belt 16 and thence onto successivesmall areas of the document D. As each small area is illuminated thecentral fibre 22 of each group picks up light from an elemental area ofthe document modulated according to the light or dark graphic matter inthe elemental area, and at its other end actuates the phototube causingit to produce electrical signals corresponding to light modulations.Because the belt carries each rider 14 on a straight line the successiveelemental areas are scanned on a straight line and the modulatedelectrical signals produced can be used in any straight line recorder.

When each rider completes its line scan it is followed after a verybrief interval by another rider. As shown in FIGS. 1 and 2, each ridercarries supply fibers 21 continuously illuminated by the lamp 23.However, under most circumstances only one pickup fiber 22 will receivelight reflected from the document D, and only one pickup fiber at a timeactuates the phototube, the system thus providing commutation of thethree pickup fibers.

To eliminate the possibility that more than one pickup fiber can actuatethe phototube during one scan, the lamp assembly can be modified asshown in FIG. 6. Within the lamp housing 39 are mounted three lamps 23a,23b and 23c disposed 120 apart on a circle and rotating within thehousing on the shaft 30. Between the anchored ends of the light supplyfibers 21 and the lamps is a light baffle 61 with an arcuate window 62extending 120 on the circle of the lamps. The baffle 61 is heldstationary on a collar 63 around the shaft 30, the collar being anchoredto the phototube housing 20. The window is disposed such that light fromone of the lamps 23a to 230 is transmitted to only one supply fiber 21at a time, namely that fiber whose other end is scanning the document.The other supply fibers are not illuminated and thus their associatedpickup fibers cannot actuate the phototube.

FIG. 7 illustrates a scanner in which a projected image rather than aphysical document is scanned. The document D is fed by rolls 6 and 9across a table 71 having a slot 72 through which a narrow line of thedocument is illuminated by lamps 73. An image D of the illuminated lineis projected by a lens 74 to a plane adjacent the scanning belt 16. Theriders 14 on the belt carry only pickup fibers 22 which lead through theshaft 30 to the phototube housing 20. The pickup fibers function as inthe scanners of FIGS. 1 to 6. The function of light supply fibers isreplaced by the lamps 73 and lens 74.

The scanning system of FIGS. 1 and 2 may also be used for recording onphotosensitive paper. As shown in FIG. 12, a lamp L is substituted forthe phototube within the light-tight housing 20. The lamp is thenexcited by electrical facsimile signals from a modulator M. Asphotosensitive paper is fed past the scanning aperture 13 (FIGS. 1 and2), a record is exposed on the paper by modulated light supplied by thelamp to the fibers 22 during each line scan of the riders 14. In thisinstance the lamp acts as an electrical signal-to-light transducer.

The scanners have been described for black and white, or monochrome,scanning, but may be used for three-color facsimile signal generation.In this case each of the three riders 14 carries a pickup fiber 21 whichis stained or otherwise filtered with one of three elemental colors. Forexample, the three pickup fibers are stained respectively red, blue andgreen, and thus act as filters each transmitting from a colored documentonly information representing one color. The rate of feed of thedocument D is slowed to one-third the speed relative to the speed of thescanning belt 16, or the scanning belt is accelerated to three timesblack and white speed, so that all three riders make a scan of eachelemental line of the docu ment. In line sequence, then, the phototubewill be actuated by three different color modulated signals and willproduce three distinct series of electrical signals in sequence for eachcomplete revolution of the belt 16.

Instead of the above described sequential color scanning, the threecolor signals may be generated simultaneously by providing each rider 14with three pickup fibers R, B, G, respectively stained red, blue andgreen at their scanning ends so that each rider scans all three coloraspects of the document during one scan. Each of the three coloredfibers transmits light of only one color aspect of the document. At theother ends of the fibers in the photocell housing 20 as shown in FIG.10, the fibers R, B and G are held in a bundle off the axis of thehollow tube 30 so that their ends move in circles concentric with acircle-to-line converter 80. The converter comprises at one end threeconcentric light-conducting tubes 81, 82 and 83 respectively oppositethe circular paths of the R, B, and G fibers. The opposite ends of thetubes are fanned out into straight line edges directed at threephotocells 24r, 24b and 24g respectively. Regardless of the angularposition of each fibre end on its circular path the converter conductslight from the fibers to their respective photocells, simultaneouslyproducing three electric color signals. These signals may be used forsimultaneous recording in color by facsimile apparatus such as is shownin U.S. Pat. No. 2,758,906.

Shown in FIGS. 8 and 9 is a modification of the scanner of FIGS. 1 and 2adapted for the scanning at either of two speeds of documents ofdifferent widths. Shown as examples are documents 5 and 11 respectivelyof 5 and 11 inches in width. In order that the two different widths bescanned at the same line frequency, the riders 14 on the scanning belt16 must traverse the 5-inch document about twice as frequently as the ll-inch. Therefore the 5-inch document must be fed lengthwise by the feedroll 6 at twice the speed of the l l-inch document. The document feedrate is doubled by throwing the lever 35a of a gear change box 35between the belt drive and the feed roll 6. Scan frequency is doubled bydoubling the number of riders 14 on the scanning belt 16. Thus there aresix riders 14 in the scanner of FIG. 8, each rider carrying at least onelight pickup fiber 21. The pickup fibers are anchored at their oppositeends in the rotating lamp housing 39 at 69 intervals. The anchored endsof the fibers are opposite six similarly positioned lamps 23a to 23f. Inthe housing 39 is a baffle 61!) with an arcuate window 62a extending onthe circle of the fibre ends and lamps, the baffle being held stationaryby a collar 63 anchored to the photocell housing 20. As shown in FIG. 9the arcuate window 620 is adjustable from 60 of arc, as shown, to by avane 66 carried on a sleeve 64 around the collar 63. The sleeve 64 has amechanical link 67 to the gearbox lever 35a and a switch 35b controllingsupply of power to lamps 23b, 23d and 23f.

With the lever 35a, vane 66 and switch 35b in the position shown inFIGS. 8 and 9 all lamps are illuminated, the window 62a is open 60 andthe feed roll 6 is turning at the faster speed for the 5-inch document5. The fiber ends for each rider 14 will be illuminated only for theperiod corresponding to 60 of arc during which the rider is traversingthe width of document 5, this traverse being slightly less than thespacing between successive riders 14 on the left 16. The pickup fibers(not shown) will thus transmit the document-modulated light to thephotocell in housing 20 only during this shorter and more frequent scanthan the l l-inch scan now to be described.

When the lever 35a, vane 66 and switch 35b are transferred from thepositions shown, the roll 6 feeds an ll-inch document 11 at about halfthe 5-inch speed, the vane 66 opens the window 62a to 120 of arc, andalternate lamps 23b, 23d and 23f are extinguished. Consequently thefiber ends on alternate riders only are illuminated during the longerinterval of a full scan corresponding to 120 of arc. The linear fiberopticscanning belt may thus be used without physical alteration both forthe faster scan of the smaller, 5-inch document, and the normal scanningspeed of the larger, 1 l-inch document.

The fiber optic-scanning belt used for single line-by-line scanning infacsimile as heretofore described is also useful for simultaneousmultiple line scanning as, for example, in character recognition. Forthis purpose, and as shown in FIG. 11, a plurality of pickup fibers 22ato 223 in the rider tube 51 of FIGS. 3 to 5 are disposed in a linearseries at right angles to the direction of scan as indicated by thearrow in FIG. 11. The series of fiber ends extends to at least theheight of the characters, e.g. "A," on a document to be scanned. Theopposite ends of the fibers are optically coupled to a set of separatephotocells similar as shown and described with reference to FIG. 10.Other fibers 21 supply light to the document as the series of fibers 22ato 22g simultaneously scan a character. As the respective portions ofthe character they view modulate the light picked up, the respectivephotocells will generate corresponding signals. The pattern ofsimultaneous signals of all the photocells may be compared with acomputer-stored pattern for identity and recognition of the scannedcharacter. Or the several signals may be transmitted to a multistylusrecorder, such as shown in US. Pat. No. 2,785,942, for simultaneousrecording.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. A graphic scanner comprising a flexible orbiting carrier, means todrive the carrier on an elongate closed path parallel to an image plane,a rotating member coupled to said Carrier to rotate in synchronismtherewith, a stationary light transducer, and a flexible lighttransmission fiber having one end connected to said carrier and movabletherewith to scan said image plane on said elongate path, the other endof said fiber being held substantially axially on said rotating memberin light exchanging relationship with said transducer, and anintermediate length of said fiber being free to flex as the distancebetween the two ends of the fiber varies.

2. Apparatus according to claim 1 wherein said other fiber end is heldby said rotating member on the axis thereof.

3. A scanner according to claim 1 characterized by a light sourcerotating on said member and an additional fiber connected between saidcarrier and light source for illuminating an elemental area of saidimage plane viewed by the first said fibre.

4. Apparatus according to claim 1 wherein said rotating member comprisesa housing and a light source mounted therein, and characterized by asecond flexible light transmission fiber having one end connected tosaid carrier adjacent the first said fiber and having its other endanchored on said housing with respect to said light source, anintermediate length of said second fiber being free to flex as thedistance between the two ends of the fiber varies.

5. Apparatus according to claim 1 wherein said rotating member comprisesa hollow shaft enclosing said fiber adjacent said light transducer.

6. Apparatus according to claim 5 wherein said transducer is mounted ina light-tight housing supporting one end of said hollow shaft adjacentthe transducer.

7. Apparatus according to claim 1 wherein said orbiting carriercomprises an endless belt. V

8. Apparatus according to claim 1 wherein said transducer comprises aphotoelectric device converting light to electrical signals.

9. Apparatus according to claim 1 wherein said transducer comprises alight source for converting electric signal modulations to lightmodulations.

10. A scanner according to claim 1 characterized by means to project animage of graphic matter on said plane.

11. A scanner according to claim 1 characterized by a plurality of lightsources carried on and rotating with said member, a plurality of fibersconnected at spaced locations on said carrier and extending to saidlight sources respectively, and a mask interposed between said fibersand light sources, said mask being stationary relative to said lamps andhaving an aperture allowing successive exposure of the fibers to therespective sources.

12. Apparatus according to claim 11 wherein said aperture comprises anarcuate slot coaxial with the locations of said fiber and light sources.

13. Apparatus according to claim 1 characterized by a plurality offibers connected between spaced locations on said carrier and saidtransducers.

14. Apparatus according to claim 1 characterized by a plurality oftransducers and a plurality of fibers optically connected between spacedlocations on said carrier and respective transducers.

15. Apparatus according to claim 14 wherein said fibers comprisecolor-filtering means for transmitting selected color aspects of saidimage plane.

16. Apparatus according to claim 15 wherein a single-color filteringmeans is associated with each said spaced location.

17. Apparatus according to claim 15 wherein a plurality ofdifierent-color filtering means are associated with each said spacedlocation.

18. Apparatus according to claim 1 characterized by a plurality offibers connected at a location on said carrier and disposed to scandifferent parallel portions of said image plane simultaneously.

19. Apparatus according to claim 18 characterized by a plurality ofphotoelectric devices, said plurality of fibers being opticallyconnected respectively between said location and said transducers.

20. Apparatus according to claim 1 characterized by means to feeddocuments through said image plane and means to change the speed of saidfeed.

21. Apparatus according to claim 20 characterized by a plurality offibers carried at one end at spaced locations of said fibers, means forilluminating the other ends of said fibers, and control meanscooperative with said speed change means for changing the number offibers lighted by said illuminating means.

22. Apparatus according to claim 1 characterized by rider carried onsaid carrier and a metal tube anchored on the rider with its open end atsaid image plane, said fiber being held in said tube to prevent flexingof the fiber adjacent the carrier.

23. Apparatus according to claim 22 wherein said tube is curved awayfrom said image plane toward said rotating member.

